1. Field of the Invention
This invention relates to a compressed air supplying device for supplying compressed air to various types of pneumatic equipment.
2. Description of the Prior Art
In supplying compressed air to pneumatic equipment such as an air cylinder, it is usually required to remove water from the compressed air so as to prevent the various obstructions which are caused by water in compressed air. Accordingly, an air dryer is usually interposed between an air compressor and the pneumatic equipment to remove water from the compressed air. Typically, the air dryer comprises a drying agent such as silica gel. However, the water absorbing function of the drying agent gradually deteriorates in response to an increase in the amount of absorbed water, and it is thus necessary to replace or regenerate the drying agent occasionally.
Japanese Utility Model Laid Open Publication No. 59-27171 shows one example of a compressed air supplying device having a regenerating device for a drying agent, wherein an air reservoir for storing regenerated compressed air is provided on the outlet side of a dryer, and dry air of a predetermined pressure is stored therein during the operation of the air compressor while when the operation of the air compressor is stopped, the dry air in the regenerating air reservoir is supplied through a pressure reducing valve to the dryer whereby the drying agent in the dryer is regenerated. However, there are shortcomings in the prior art device since the air reservoir which exclusively stores regenerating compressed air is disadvantageous in view of the cost involved and the space required for its installation.